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Pre – AP 10/11 Warm – UP Notes Enzymes and Bioenergetics

(CH 2 section 4)HW: Print Enzyme Lab (posted

today)Study for Quiz FRIDAY.Check your assignment for PSAT

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Warm - UP What are enzymes and what do

they do?

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EnzymesEnzymes

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What Are What Are Enzymes?Enzymes?

Most enzymes are Proteins Proteins ((tertiary and quaternary structures)

Act as CatalystCatalyst to accelerates a reaction

Not permanentlyNot permanently changed in the process

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EnzymesEnzymes Are specific for

what they will catalyzecatalyze

Are ReusableReusable End in –asease

-Sucrase-Sucrase-Lactase-Lactase-Maltase-Maltase

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How do enzymes Work?How do enzymes Work?Enzymes work

by weakening weakening bondsbonds which lowers owers activation energy

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EnzymesEnzymes

FreeEnergy

Progress of the reaction

Reactants

Products

Free energy of activationFree energy of activation

Without EnzymeWith Enzyme

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Enzyme-Substrate Enzyme-Substrate ComplexComplex

The substancesubstance (reactant) an enzymeenzyme acts on is the substratesubstrate

EnzymeSubstrate Joins

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Active SiteActive Site A restricted regionrestricted region of an enzymeenzyme molecule

which bindsbinds to the substratesubstrate.

EnzymeSubstrate

Active Site

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Induced FitInduced Fit A change in the

shapeshape of an enzyme’s active site

Induced Induced by the substrate

Different from lock and key analogy

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Factors Affecting Enzyme Factors Affecting Enzyme ActivityActivity

Temperature pH Cofactors & Coenzymes Inhibitors

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Temperature & pHTemperature & pH

Most enzymes like near neutral pH (6 to 8)

Denatured (unfolded) by ionic saltsionic salts High temperaturesHigh temperatures are the most

dangerous reactions & denaturedenature enzymes (Most like normal Body (Most like normal Body temperaturestemperatures)

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Cofactors and CoenzymesCofactors and Coenzymes Cofactors: Inorganic substancesCofactors: Inorganic substances (zinc, (zinc,

iron) iron) and Coenzymes: Coenzymes: vitaminsvitamins (organic) are

sometimes need for proper enzymatic enzymatic activityactivity.

Example:Example: IronIron must be present in the

quaternary structure of hemoglobinhemoglobin in order for it to pick up oxygenoxygen.

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Two examples of Enzyme Two examples of Enzyme InhibitorsInhibitors

a. a. Competitive inhibitorsCompetitive inhibitors:: are chemicals that resembleresemble an enzyme’s enzyme’s normal substratenormal substrate and competecompete with it for the active siteactive site.

EnzymeCompetitive inhibitor

Substrate

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InhibitorsInhibitorsb.b. Noncompetitive inhibitorsNoncompetitive inhibitors::

Inhibitors that do not enter thedo not enter the active siteactive site, but bind tobind to another partanother part of the enzymeenzyme causing the enzymeenzyme to change its shapechange its shape, which in turn alters the active sitealters the active site.

Enzymeactive site altered

NoncompetitiveInhibitorSubstrate

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BIOENERGETICBIOENERGETICSS

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What is Bioenergetics?The study of

energyenergy in living systemsliving systems (environments) and the organismsorganisms (plants and animals) that utilize them

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Energy Required by

all organisms

May be Kinetic or Potential energy

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Kinetic Energy Energy of Motion Heat and light energy

are examples

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Kinetic Energy

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Potential Energy EnergyEnergy of of

positionposition Includes Includes

energy energy stored in stored in chemical chemical bonds; bonds; chemical chemical gradientsgradients

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Two Types of Energy Reactions

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Endergonic Reactions

Chemical reactionChemical reaction that requires a net input of energyenergy. (energy absorbing)

PhotosynthesisPhotosynthesis

6CO2 +6H2O C6H12O6 + 6O2

SUNphotonsphotons

LightEnergy

(glucose)(glucose)

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Exergonic Reactions Chemical reactionsChemical reactions that

releases energy (energy releases energy (energy releasing)releasing)

Cellular Respiration

C6H12O6 + 6O2 6CO2 + 6H2O+ATP(glucose)(glucose)

EnergyEnergy

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Metabolic Reactions of

Cells

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What is Metabolism?

The sum sum totaltotal of the chemical chemical activitiesactivities of all cellscells.

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Two Types of Metabolism

Anabolic Anabolic PathwaysPathways

Catabolic Catabolic PathwaysPathways

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Anabolic PathwayAnabolic Pathway Metabolic reactions,Metabolic reactions, which

consume energyconsume energy (endergonic),(endergonic), to buildbuild complicated molecules from simpler compounds.

PhotosynthesisPhotosynthesis

6CO2 + 6H2O C6H12O6 + 6O2

SUNlightlightenergyenergy

(glucose)(glucose)

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Catabolic PathwayCatabolic Pathway Metabolic reactionsMetabolic reactions which

release energyrelease energy (exergonic)(exergonic) by breaking downbreaking down complex molecules in simpler compounds

Cellular RespirationCellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O +

ATP(glucose)(glucose)

energy

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Cellular Energy - Cellular Energy - ATPATP

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ATPATP Components:Components:

1. adenine: nitrogenous 1. adenine: nitrogenous basebase2. ribose:2. ribose: five carbon sugar five carbon sugar3.phosphate group: chain 3.phosphate group: chain of 3of 3

riboseribose

adenineadenine

P P P

phosphate groupphosphate group

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Adenosine Adenosine TriphosphateTriphosphate

Three Three phosphate phosphate groups-groups-(two(two with high with high energy bondsenergy bonds

Last Last phosphatephosphate group (POgroup (PO44) ) contains the contains the MOST energyMOST energy

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Breaking the Bonds of Breaking the Bonds of ATPATP

Process is called phosphorylationphosphorylation

Occurs continually in cells

Enzyme ATP-aseATP-ase can weaken & break last POlast PO44 bondbond releasing energy & free PO4

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How does ATP How does ATP work ?work ? Organisms use enzymesenzymes to

break down energy-rich energy-rich glucoseglucose to release its potential energy

This energy is trapped and stored in the form of adenosine adenosine triphosphate(ATP)triphosphate(ATP)

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How Much ATP Do Cells How Much ATP Do Cells Use?Use?

It is estimated that each celleach cell will generate and consume approximately 10,000,000 10,000,000 molecules of molecules of ATP ATP per secondper second

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Coupled Reaction - Coupled Reaction - ATPATP The exergonic exergonic

hydrolysishydrolysis of ATPATP is coupled with the endergonic endergonic dehydration dehydration processprocess by transferringtransferring a phosphate groupphosphate group to another molecule.

HH22OO

HH22OO

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Hydrolysis ofHydrolysis of ATP ATPATP + H2O ADP + P (exergonic)

HydrolysisHydrolysis(add water)(add water)

P P P

Adenosine triphosphate (ATP)Adenosine triphosphate (ATP)

P P P++

Adenosine diphosphate (ADP)Adenosine diphosphate (ADP)

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Hyrolysis is ExergonicHyrolysis is Exergonic

EnergEnergy y

Used Used by by

CellsCells

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Dehydration ofDehydration of ATP ATPADP + ADP + P P ATPATP + + HH22O O (endergonic(endergonic)

P P P

Adenosine triphosphate (ATP)Adenosine triphosphate (ATP)

P P P++

Adenosine diphosphate (ADP)Adenosine diphosphate (ADP)

DehydrationDehydration(Remove (Remove HH22OO

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Dehydration is Dehydration is EndergonicEndergonic

Energy Energy is is restorerestored in d in ChemicChemical al BondsBonds

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ReviewReview

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How many high energy How many high energy phosphate bonds does phosphate bonds does

ATP have?ATP have?

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Which is true of Which is true of photosyntheis?photosyntheis?

Anabolic Anabolic or or CatabolicCatabolicExergonicExergonic OrOrEndergonicEndergonic

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The breakdown of ATP is The breakdown of ATP is due to:due to:

DehydrationDehydration ororHydrolysisHydrolysis

HH22O addedO added oror HH22O removedO removed

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Which Reactions are Which Reactions are often Coupled in often Coupled in

OrganismsOrganisms

HydrolysisHydrolysis or or DehydrationDehydration

AnabolismAnabolism or or CatabolismCatabolism

EndergonicEndergonic oror ExergonicExergonic

BOTHBOTH

BOTHBOTH

BOTHBOTH